This present invention relates generally to semiconductor manufacturing equipment. More specifically, the present invention relates to temperature control of semiconductor manufacturing equipment. Merely by way of example, the invention has been applied to a self-cooling gas delivery apparatus used with a high density plasma processing chamber. The method and apparatus can be applied to other applications as well such as self-cooling of gas delivery nozzles and the like.
Chemical vapor deposition (CVD) is a gas reaction process used in the semiconductor industry to form thin layers or films of desired materials on a substrate. Some high density plasma (HDP) enhanced CVD processes use a reactive chemical gas along with physical ion generation through the use of an RF-generated plasma to enhance the film deposition by attraction of the positively charged plasma ions onto a negatively biased substrate surface at angles near the vertical to the surface, or at preferred angles to the surface by directional biasing of the substrate surface. One goal in the fabrication of integrated circuits (ICs) is to form very thin, yet uniform films onto substrates, at a high throughput.
Gas nozzles are used in many CVD chambers as part of the gas delivery system. for example, process gases used in the thin film deposition process enter the chamber through one or more gas nozzles disposed on interior surfaces of the chamber. The gas nozzles are made of a variety of materials, including ceramics. Depending on the chamber design, some CVD processes, and particularly plasma assisted CVD processes operates at high temperatures and subject the gas nozzles to plasma heating inside the chamber. These nozzles, which are typically ceramic nozzles with one or more orifices located at the distal end, can reach temperatures as high as about 800° C. or higher during typical HPD CVD processes. These high temperatures may result in the premature dissociation of process gases inside the nozzle, rather than near the substrate, resulting in the creation of reaction byproducts that are subsequently incorporated into the film. These undesired processes may cause non-uniformities and particles in the deposition process along with other problems.
Therefore, there is a need in the art for a self-cooling gas delivery apparatus for use in HDP-CVD and other semiconductor processing apparatus.